1. Field of the Invention
This invention relates to (i) 2-oxy-4H-3,1-benzoxazin-4-ones and the pharmaceutically acceptable acid addition salts thereof; (ii) the use of these compounds as serine protease inhibitors in humans and animals; (iii) pharmaceutical compositions comprising a compound of this invention and at least one pharmaceutical excipient; and (iv) processes for preparing the compounds of this invention.
2. Related Art
The compounds of this invention are 2-oxy substituted derivatives of 4H-3,1-benzoxazinones having the following structure: ##STR2##
2-Ethoxy-4H-3,1-benzoxazin-4-one is disclosed in British Patent Specification No. 1,389,128 and in the corresponding German Offenlegungschrift No. 2241012. A few 4H-3,1-benzoxazin-4-ones are known to possess enzyme-inhibitory activity. Teshima et al. have disclosed various 2-alkyl-4H-3,1-benzoxazin-4-ones reported to be active as enzyme inhibitors (J. Biol. Chem., 257, 5085-5091, 1982). 4H-3,1-benzoxazin-2,4-dione has been disclosed as having enzyme inhibitory activity (Moorman, A. R., and Abeles, R. H. J. Amer. Chem. Soc. 104, 6785-6786, 1982). 2-Ethoxy-4H-3,1-benzoxazinone and 2-(trifluoromethyl)-4H-3,1-benzoxazinone inhibit chymotrypsin (Hedstrom et al, Biochemistry 23, 1753-1759, 1984).